Add rule to forbid asyncio.create_task

[Tinche]

Description

I'd like to enforce structured concurrency in my codebases, and a rule to forbid asyncio.create_task would be very helpful, since it would enforce all tasks are managed through TaskGroups.

This is likely to be controversial and spawn false positives so I think it should probably be disabled by default. Obviously it's possible to achieve structured concurrency even with asyncio.create_task, but I would argue you'd just be reimplementing TaskGroups.

Still, for some codebases I think a rule like this would be very useful.

[AlexWaygood]

I can see the appeal. Unfortunately I think this is probably much too opinionated to be done until we recategorize our ruleset so that we can better distinguish highly opinionated, restrictive rules like this one from rules that nearly everybody would probably want enabled :( See #1774 for the recategorisation issue